mcneil



( o Model.)

M. MQNEIL. PRESSURE G No. 445,355. Patented Jan 27,1891.

INVENTDR:

m2 W m w W UNITED STATES PATENT OFFICE."

MURDOOK MCNEIL, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO THE EMPIRE STEAM GAUGE COMPANY, OF SAME PLACE.

PRESSURE-GAG E.

PEGIFIGATION forming part of Letters Patent No. 445,355, dated January 27, 1891.

Application filed July 5, 1890. Serial No. 357,840%- (No model.)

To all whom it may concern: motion to the segmental lever and through Be it known that I, MURDOCK MGNEIL, of the latter to theindex or pointer. hen the Boston, in the county of Suffolk and State of gage is in good order, the index should al- Massachusetts, have invented certain new ways go back to zero when the pressure is re- 5 and useful Improvements in Steam-Pressure moved. It has been found. however, that the Gages, of which the following is a specificaspring-tube A has a tendency to lose its elastion. ticity by use, so that the gage is often ren- This invention relates to pressure-gages dered unreliable. in which the spring which actuates the in- My invention is intended to remedy the 1o dex or pointer is a bent metal tube usually above-mentioned defect, and it is carried into of a flattened or elliptical shape in cross-secpractice as follows: tion. The connection between the gage and (t represents a spring, preferably helical in boiler is made by a pipe in which the steam form, suitably secured at its outer and inner is condensed, the water of condensation fillends to lugs or nuts b b. The nut Z2 at the P ing the said spring and receiving the steamouter end of said springis adapted to receive pressure, so that the curvature of the spring a screw 0, and the nut b at the inner end of varies with the steam-pressure, the movethe spring receives a screw (1, having its ment given the free end of the spring by the lower end provided with a slot 6 to receive an variation of its curvature being imparted ear f, formed on a clamp g, surrounding the are through suitable mechanism to the indicator tube A, and secured thereon by a screw 72., or pointer, as shown in the Bourdon patent, the arrangement being such that a jointed No. 9,163. connection is formed between the tube and The invention has for its object to provide spring by a pin t' passing through the earf improved means for securin to the spring and screw 0, as will be clearly understood by 7 5 25 and easing an auxiliary spring which shall reference to Fig. supplement the curved spring and prevent j represents a bushing, which is suitably the loss of elasticity of the latterfrom affectfitted into the casing A and through which ing the operativeness of the apparatus; and passes the screw 0, the latter being provided to this end the invention consists in the imwith a left-hand screw-thread and adj ust-ably 8o 30 provements which I will now proceed to de secured by jam-nuts 7t k.

scribe and claim. It is obvious that by means of the screw 0 In the accompanying drawings, forming a the pressure of the spring a 011 the springpart of this specification, Figure 1 represents tube A may be adjusted to any desired exa front view of a steam-gage embodying my tent. It will be seen that the force of the 3 5 improvements, the dial-plate being removed. spring (I. is always exerted to keep the tube Fig. 2 represents a section on line 2 2, Fig. l. in its normal position, or that which it occu- The same letters of reference indicate the pies when the pointer H is at zero, and that same parts in all the figures. whenever the steam-pressure operates to vary In the drawings, A represents the bent the curvature of the tube A it must also op 40 metal tube, one end of which is rigidly aterate against the spring a, said spring receivtached to the casing A andthe other end to ing all the pressure and being compressed to a rod B, which is connected at O to a lever an extent corresponding to the displacement 'D, which is fulcrumed at I and has a toothed of the tube A, so that its force is exerted to segment E at its other end. The latter gears compel the tube A to return to the proper 5 5 into a pinion F, Fig. 2, on the spindle G of point when the pressure decreases.

the index or pointer H. My improvement can be easily applied to The construction above described in COlIlany gage of this class and is not limited to 111011 and of itself forms no part of my invensteam-pressure gages. tion. When the water is forced up by the Another important function of the spring {00 '"o steam-pressure into the tube A, the tendency a is to prevent the vibration of the pointer of said tube is to straighten, and thus impart H by the jar of the machinery with which it is connected. The spring a may be of other than spiral form, if preferred, although I prefer the spiral form as the most convenient.

I am aware that an auxiliary spring has been before employed in connection with a Bourdon spring. Hence I donot claim, broadly, the combination of an auxiliary spring with a Bourdon spring.

I claim- 1. In a pressure-gage, the combination of the casing, the spring-tube A therein, the spring a, interposed between the casing and the tube, a holder or support for the outer end of said spring, attached to the casing, a clamp attached to the tube, a nut or collar engaged with the inner end of the spring, and a hinge or joint connecting the collar with the clamp, as set forth.

- 2. In a pressure-gage, the combination of the casing, the tube A therein, the spring a,

interposed, between the casing and the tube, the adjusting-screw c, engaged with the easing and supporting a nut which is engaged with the outer end of the spring a, the clamp g, attached to the tube, the nut or collar 1), engaged with the inner end of the spring, and the hinge or joint connecting said collar Z) with the clamp g, as set forth.

In testimony whereof I have signed my narneto this specification, in the presence of two subscribing witnesses, this 1st day of July, A. D. 1890.

MURDOCK MCNEIL.

Witnesses:

O. F. BROWN, A. D. HARRISON. 

